求极限lim arctan(x^2-2x)/sin3πx.当x趋向2时,

来源:学生作业帮助网 编辑:作业帮 时间:2024/07/13 11:46:52
求极限lim arctan(x^2-2x)/sin3πx.当x趋向2时,
x){ټƗ3'd*$%$iTUhgo{wrŋmO'L4z6}MR>Q 5ِo-THkf4u(u tu6<ٽ&lz&<|m۟M_|uj|>eP݋.xҶ@y>\F~4P̊DWD <<;h(ڀ9`+> &c&UkAf 3.(VAA_b8]eV

求极限lim arctan(x^2-2x)/sin3πx.当x趋向2时,
求极限lim arctan(x^2-2x)/sin3πx.
当x趋向2时,

求极限lim arctan(x^2-2x)/sin3πx.当x趋向2时,
sin3πx=sin(3πx-6π),
当x->2, 3πx-6π->0, 所以3πx-6π是sin3πx=sin(3πx-6π)的等价无穷小,可以用等价无穷小的代换.
lim arctan(x^2-2x)/sin3πx
=lim(x^2-2x)/(3πx-6π)
=limx(x-2)/[3π(x-2)]
=lim[x/(3π)]
=2/(3π)

lim(x->2) arctan(x^2-2x)/sin(3πx) (0/0)
=lim(x->2) {(2x-2)/[1+(x^2-2x)^2]} / [3πcos(3πx)]
=2/(3π)